I am hoping to bring a product to market based on the work of researcher H. Y. Mohan Ram. I am happy to provide a link to Ram’s work if need be.
The Formula:
Part A: .5 grams silver nitrate is stirred into 500ml. distilled water
Part B: 2.5 grams sodium thiosulfate (anhydrous) is stirred into 500ml. distilled water.
The silver nitrate solution (A) is then mixed into the sodium thiosulfate solution (B) while stirring rapidly. The resulting blend is stock silver thiosulfate solution.
The Questions:
How would I determine the “shelf-life” of the stock silver thiosulfate solution, assuming that it is kept in a light tight container at room temperature?
Let’s assume that the stock silver thiosulfate solution has a short shelf-life. Given this, how would I determine the shelf-life of aqueous solutions A and B if they are kept separate in light tight containers held at room temperature?
Any info, link to a resource, etc. would be greatly appreciated.

A search shows silver thio is used in horticulture to change sex of plants , preserve cut flowers ...

It seems to me the best way to do this is to sell as sachets of the dry base chemicals. One sale contains one 0.5 gm sachet of sliver nitrate and one 2.5 gm sachet of sodium thio ...both have unlimited shelf life ... the end user can add both to 1/2 liter of tap water (any impurities in the water will have minimal effect ) then add the solutions together ...

Selling with the water added causes all sorts of problems , high shipping costs , risk of leakage in shipping , cost of bottles ...

Cost of sodium thio is less than 1c per gram

0.5 gm silver nitrate contains about 0.3 gm of silver , value 15c ... 0.5gm silver nitrate should not cost you more than 40c ... if it does make it yourself from silver and nitric acid.

Cost of the two sachets to make will not be more than half a $ including packaging ...
But most importantly , can be sent in an envelope in the post for the price of letter mail keep the sachets with a large area and thin (flat)....

Yes it appears silver thio has a limited life ... Aqueous A and B however kept in the dark
should have unlimited life since there is no mechanism to cause a breakdown... If in doubt put some in your fridge to test ...